Bochy's decision was a little surprising because Cain lost the honor after one season. But it was his worst since 2006, his first full year in the majors. Conversely, Bumgarner had a breakout 2013 and established himself as one of the best left-handers in the majors.

Bumgarner was not available for comment, but Cain said he was "pumped" for his teammate.

"I'm excited to watch him go out there and start Opening Day and get the season started off right for us," Cain said. "It's such an honor to be able to go out there and pitch that first game. He's more than deserving."

Cain also said Bumgarner was "kind of in shock and a little bit in awe" when Bochy delivered the news.

Bochy cautioned he might "tweak" the rotation after Cain, but Hudson is scheduled to pitch the April 8 home opener. But the first two slots are set.

"I'd be comfortable with either one going the first game," Bochy said. "This is more of a reward for Madison. He had a real nice year. He hasn't done it before. We'll check that box off in his career. There's no ego with these guys. Matty, he's fine with this, and we've had a lot of success with Matty being No. 2."

Bumgarner likely will face lefty Patrick Corbin in the March 31 opener at Arizona and could face Clayton Kershaw in Los Angeles on April 5. Bumgarner has won two of his three meetings against the reigning Cy Young winner.

Briefly: Yusmeiro Petit will start Wednesday's Cactus League opener against the A's. The Giants are off Thursday. Bumgarner and Vogelsong will pitch against the Brewers on Friday, Cain will face the Cubs on Saturday, Hudson the Diamondbacks on Sunday and Lincecum the Padres on Monday. ... Pitching prospects dominated Tuesday's intrasquad game, which ended 0-0. Kyle Crick,Kendry Flores, Ty Blach and Jose Casilla had 1-2-3 innings. Derek Law and Edwin Escobar were not as sharp. ... Angel Paganwill join Marco Scutaroand Buster Posey on the bench Wednesday. Bochy is being cautious after Pagan's back tightened Sunday.